This invention relates to circularly polarized antennas and, more particularly, to such antennas using slotted conductive cylinders.
Although television has been broadcast in horizontal polarization in the U.S.A., it appears from recent test results that circularly polarized broadcasting might well greatly improve television reception in large metropolitan areas. Further, broadcast antennas must often broadcast an omnidirection pattern about the tower such that when this tower is erected in the center of a city, for example, substantially equal coverage is provided about the city.
Slot antennas like that described by Bazan in U.S. Pat. No. 2,981,947 are presently being used for providing horizontally polarized television broadcasting. This type of antenna provides a good omnidirectional pattern. Since broadcasters have expended considerable cost for this slot type antenna, it would be desirable to provide some means of converting this type of antenna to provide a circularly polarized broadcasting antenna. This is especially true for UHF stations where the operating budgets are smaller and there is a wide use of the slot antenna.